Studies on Elimination Pathways of β-Halovinyl Ketones Leading to Allenyl and Propargyl Ketones and Furans under the Action of Mild Bases
作者:Hun Young Kim、Jian-Yuan Li、Kyungsoo Oh
DOI:10.1021/jo302253c
日期:2012.12.21
stereochemically defined β-halovinyl ketones has been investigated using a mild base, NEt3, leading to the formation of allenyl ketones and propargyl ketones. A preferential α-vinyl enolization of (E)-β-chlorovinyl ketones has been observed where a nonplanar s-cis conformation is proposed as a dominant conformation as opposed to a planar s-cis conformation of (Z)-β-chlorovinyl ketones. Other eliminative pathways
1,3-Dienones and 2<i>H</i>-Pyran-2-ones from Soft α-Vinyl Enolization of β-Chlorovinyl Ketones: Defined Roles of Brönsted and Lewis Base
作者:Hun Young Kim、Kyungsoo Oh
DOI:10.1021/acs.orglett.5b03265
日期:2015.12.18
The eliminative reaction pathways of (E)-β-chlorovinyl ketones were investigated in the presence of both Brönsted and Lewis bases. The Brönsted base, Et3N, effected the soft α-vinyl enolization of (E)-β-chlorovinyl ketones to [3]cumulenol intermediates; in turn, a catalytic amount of Lewis base, PPh3, initiated isomerization to provide 1,3-dienones in high yields. The introduction of a carbon-based
在布朗斯台德碱和路易斯碱的存在下研究了(E)-β-氯乙烯基酮的消除反应途径。布朗斯台德碱Et 3 N影响了(E)-β-氯乙烯基酮向[3]异丙苯三酚中间体的软α-乙烯基烯醇化作用。进而,催化量的路易斯碱PPh 3引发了异构化反应,以高收率提供了1,3-二烯酮。将碳基亲核试剂引入反应混合物中,可在一锅中高效合成2 H -pyran-2-one,其中碳基亲核试剂是由额外等价的布朗斯台德碱Et 3生成的N,攻击亲电的[3]枯烯酚中间体以起始环化,得到2 H-吡喃-2-酮。
A facile synthesis of 3,4-dimercaptofurans via sulfenylation of (E)-β-chlorovinyl ketones and 1,2-sulfur migration
作者:E. Song、H. Y. Kim、K. Oh
DOI:10.1039/c6ob02772e
日期:——
The one-pot sulfenylation of (E)-β-chlorovinyl ketones was investigated under soft α-vinyl enolization conditions. Modulating the nature of nucleophilic species using a “hard” base the regioselective formation of α,γ-dithio-allenyl ketones has been achieved, where the thermodynamic control was mimicked by the presence of Et3N·HCl. The sulfenylated products, α,γ-dithio-allenyl and α,α-dithio-propargyl
Ambivalent Reactivity Modes of β-Chlorovinyl Ketones: Electrophilic Lithium [3]Cumulenolates from Soft Vinyl Enolization Strategy
作者:Hun Young Kim、Edward Oscar Rooney、Raymond Phillip Meury、Kyungsoo Oh
DOI:10.1002/anie.201302750
日期:2013.7.29
Soft spot: The softvinylenolization of (E)‐β‐chlorovinyl ketones results in the in situ generation of electrophiliclithium [3]cumulenolates, which react with nucleophiles such as another lithium [3]cumulenolate to stereoselectively form vinyl allenones. They can also react with ketimine esters to give 3‐methylenepyrrolidines.
A Soft Vinyl Enolization Approach to α-Acylvinyl Anions: Direct Aldol/Aldol Condensation Reactions of (<i>E</i>)-β-Chlorovinyl Ketones
作者:Hun Young Kim、Jian-Yuan Li、Kyungsoo Oh
DOI:10.1002/anie.201209876
日期:2013.3.25
Synthesizing the synthons: The development of α‐acylvinyl anion synthons has been achieved using direct α‐vinyl enolization of α,β‐unsaturated ketones under mild reaction conditions. The synthetic utility of such synthons has been demonstrated in intermolecular aldol and aldol condensation reactions, which provide synthetically useful allenyl ketone and enyne derivatives.